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DOI: 10.1055/s-0032-1321086
Three cycloartane saponins from Astragalus tmoleus var. tmoleus
Astragalus tmoleus Boiss var. tmoleus is an endemic plant from Turkey [1]. Our phytochemical investigation on the CH2Cl2 extract of this plant led to the isolation and characterization of three known cycloartane-type saponins, astragaloside IV (1) [2], cyclocephaloside II (2) [3] and astrasieversianin I (3) [4] by using various solid/liquid chromatographic techniques. The identification of these compounds was mainly achieved by 1D and 2D NMR spectroscopic techniques (1H-1H COSY, NOESY, HSQC, HMBC), FABMS and by comparison of their spectral data with those previously reported. Our results confirm that triterpene saponins belonging to the cycloartane-type skeleton might be chemotaxonomically significant to the genus Astragalus. Although 1, 2 and 3 have previously been isolated from several species including A. membranaceus Bunge., A. microcephalus Willd and A. gilvus Boiss. [2–4], it is the first time that these compounds have been isolated from A. tmoleus var. tmoleus.
References: 1. Davis, P.H. (1989) Flora of Turkey and East Agean Islands, University of Edinburgh University Press, 7, 857–861. 2. Kitagawa, I. et al. (1983) Chem. Pharm. Bull. 31: 698–708. 3. Bedir, E. et al. (1998) J. Nat. Prod. 61: 1469–1472. 4. Tabanca, N. et al. (2005) Biochem. Syst. Ecol. 33: 1067–1070.